The light-emitting efficiency of an LED lamp not only depends on quality of LED lamp bulb, but more importantly also depends on the temperature of the LED lamp during operation, especially when a high-power LED lamp is in operation, once the temperature is above 55° C., the light-emitting efficiency thereof reduces by about 2% for each degree increase in temperature, and therefore, cooling treatment is very important when an LED lamp, especially a high-power LED lamp is in operation. In the prior art, the high-power LED lamp is usually cooled by air cooling or with a semiconductor cooling device. The feature, that different temperatures are generated at a hot end and a cold end of a P-type semiconductor element and an N-type semiconductor element while being energized, has been widely applied in the field of manufacturing a semiconductor cooling or heating device. Currently, when the N-type or P-type semiconductor elements are used to manufacture a cooling device, directions of the N-type or P-type semiconductor elements are always not taken into account, that is, when the N-type or P-type semiconductor elements are connected, the head end and the tail end of the N-type or P-type semiconductor elements are not distinguished, but arbitrary ends of the N-type or P-type semiconductor elements are connected mutually, such a mode of connection irrespective of the head end and the tail end not only reduces working efficiency of the semiconductor element, increases energy consumption, but also makes the manufactured cooling device fail to reach a required cooling temperature. Generally speaking, in terms of the cooling device manufactured with the traditional method, the temperature difference between the hot end and the cold end thereof only can reach about 60 degrees. Accordingly, the effect of usage of the existing P-type semiconductor elements and N-type semiconductor elements for manufacturing a cooling device, especially a high-power LED lamp cooling device is less than desired.